This is the traditional role of prediction markets. Pretty fascinating at predicting "group" consensus with a group of people not just being polled. They were a self-selecting group that entered a poll because they were confident enough to put their money where their mouth was. For binary events, such as Romney vs. Obama's election, they were pretty good .... but really hovered around 45c/55c for a long time (out of a $1 pay-out). then rapidly shifted about a week or so before the election.

The government didn't know how to deal with them, so both the gaming (gambling) regulatory folks and the SEC ganged up and shut down prediction markets (esp. InTrade) in the US.

How do you think they will treat bitcoin? If it's money, your violating securities law (if not set up correctly). If it's not money (poker chips), you are violating gaming laws. And of course, the IRS doesn't care: they just want 40% of your winnings. Which is pretty crazy. You bet $0.60 for a $1.00 payout. And they take $0.40. No return. How do you see getting around this?